This invention relates to an acousto-optic isolator for use in optical transmission systems or optical sensor systems.
Semiconductor diode lasers are sensitive to changes in their output loading and it is therefore desirable to protect them from optical power reflected from the system. Hence the need for some sort of unidirectional optical isolator. Traditionally magnetic effects, such as Faraday rotation, are used in conjunction with polarisation filters to establish non-reciprocal behaviour in the optical path, but this mechanism is weak in normally used optical transmission media. Moreover, integrated optical solutions using this technique appear unlikely.